1. Field of Invention
The present invention relates to memory technologies, and in particular to memory systems and methods for controlling nonvolatile memory.
2. Description of Related Arts
With the rapid development of integrated circuit, the use of portable electronic products is becoming more and more widely, so that the development of a system-on-chip (SoC) is promoted. The system-on-chip referring to a complete system integrated on a single chip, generally includes central processing unit (CPU), read-only memory (ROM), random access memory (RAM), nonvolatile memory, such as Flash/EEPROM, and other functional modules. Among them, the RAM is a module which is the most frequently used and the most frequently interacts with the CPU in the system. The nonvolatile memory belongs to slow-speed memory, and especially the time consuming of write operation of the nonvolatile memory is quite long.
In the conventional technologies, a write cache is added to improve the system performance generally. When the write operation is to be performed to the nonvolatile memory, the data is first written into the write cache, so that the system can perform other operations. A nonvolatile memory controller at the same time writes the data in the write cache into the nonvolatile memory, in order to realize the write operation to the nonvolatile memory. Thus, through the cache effect of the write cache, the system can temporarily store the data to be written into the nonvolatile memory in the write cache rapidly, in order to perform other operations. Comparing with writing data to the nonvolatile memory directly, the write time of the system can be reduced, and the performance of the system is improved.
However, as the write operation to nonvolatile memory is not performed frequently, the corresponding write cache is in an idle state in most of the time, which renders the waste of resources.